Various automatic machines have been developed for loading cases or corrugated cartons with different articles. In prior developments of such machines, many problems arose with the loading of products vertically into top opening cases or horizontally from one side or an end. Such problems were solved to a large degree by a method and apparatus for loading articles up into the bottom of a case, as disclosed in my earlier U.S. Pat. No. 3,605,377 and in my later U.S. Pat. No. 4,481,752. However, both of these patents cover apparatus for loading one-piece cases such as a regular slotted carton (RSC), wherein the top flaps of the carton are folded and sealed after the case is loaded. Such cases are satisfactory for use when the articles being loaded are dimensionally uniform and there is consistently ample room for bending the top flaps into their proper closing position. However, a serious problem arose in situations where a stack of articles to be loaded consistently varied in total height even though the number of articles was always the same for each case load. For example, in the shipment of paper in sheet form, the height of 1000 paper sheets might vary significantly from stack-to-stack. Thus, when it is necessary to ship such products in a case, it was impractical and inefficient to use an RSC type case. If the height of the case was sized to accommodate a selected number of paper sheets, the inherent variations in paper sheet thickness often caused some stacks to be too short or too high. If too short, an empty space was created above the paper in the case which was inefficient and also reduced the carton's ability to withstand stacking during shipment or storage without crushing. To counteract this, it was necessary to add dunnage to the empty space. If the paper stack was too high, the RSC case top flaps could not be folded and sealed properly. Accordingly, it was found to be necessary to utilize an open-top, half-slotted case (HSC) with a separate telescoping top. Moreover, it became apparent that to maximize the efficient use of case space, the open-top case was preferably sized in height so that the stack of articles being loaded would always fully occupy the carton space. This meant that in many instances the stack of articles when loaded would extend slightly above the top edge of the open-top case. The problem which then arose was to provide a machine capable of automatically installing a properly fitting top or lid to a case and more particularly to provide this lidding operation as part of a machine that performs the initial loading function.
A general object of the present invention is to provide an automatic packaging machine that solves the aforesaid problem.
More specifically, another object of the invention is to provide a packaging machine that will automatically load a stack of articles through the bottom of an open-ended shipping case, close and seal the bottom flaps of the case and then install a telescoping lid covering the loaded articles and fitting it around the upper end of the carton.
Another object of the invention is to provide an automatic packaging machine for bottom loading cases with a stack of product and installing telescoping lids to the cases in a rapid manner while providing consistently uniform folding and positioning of lid flaps and thus a snug fitting of the lid for each case despite variations in the height of product stacks being loaded therein.
Another object of the present invention is to provide an automatic packaging machine for installing a lid on a loaded, open-top case wherein the lid is provided as a scored sheet, positioned on top of the case and then is folded and glued into a telscoping configuration on the case.
Still another object of the present invention is to provide an automatic packaging machine for bottom loading a carton and installing a telescoping lid thereon that is particularly efficient and will operate at a relatively high output rate with maximum reliability and minimal maintenance.